Lakota Beaded and Quilled Doll 1880-1890  beaded doll from the early Reservation period, possibly Pine Ridge Agency

This is what I think you have.. I wish I had this in my hands, so I can see if thread is cotton or skew.. is leather new or buffalo. hair Buffalo tail hair,  Most dolls with Quills are Lakota..

I'm Shoshone (Indian). Do you live near the Lakota   Sioux Resevation? I would take this to the Tribal Council and see if they would buy it or just tell you 100% it's Lakota doll. ..send then photos...The really well dressed dolls like this sell for $1000.00s.. 

Cheyenne   Doll, early 20th century, Northern or Southern Plains, Buckskin, hair, beads, cloth, pigment,   This also what I think it is. but leanning more to Lakota. because use of Quills..Cheyenne used lots of handmade bells.... I wish you lots of luck on this Doll.    

thread and sinew-sewn Some of the  dolls sell at auction for only $ hundreds.. $100.00 to $800.00.. 

Good Luck
 

http://www.pilotguides.com/articles/the-lakota-tribes-of-the-great-plains/   

start here good story.